1. Field of the Invention
This invention relates to and has among its objects the provision of novel injection sites and methods for making them. In particular, one of the objects of the invention is the provision of improved injection sites for medicament injection devices in assemblies used in the administration of parenteral fluids. Further objects of the invention will be evident from the following description.
2. Description of the Prior Art
Customarily, in hospitals supplementary medicaments are administered via hypodermic syringe through resealable, puncturable closures on devices attached to intravenous administration sets which are delivering parenteral solutions or the like to patients. Typical of such devices are those disclosed in U.S. Pat. Nos. 3,332,418 and 3,776,229.
Sterile parenteral solutions are frequently supplied to medical institutions in sterile receptacles. Part of the receptacle is filled with parenteral solution, the remainder is filled with air to allow supplementary medicaments to be added to the sealed containers prior to administration of the solutions to patients. Generally, these receptacles include an injection site through which the aforementioned medicaments can be injected by means of a hypodermic syringe. Usually, the syringe needle is forced through a resealable or self-sealing, puncturable member formed from a resilient material such as rubber. The puncturable member or closure is thus one part of the injection site.
Usually, the puncturable member is secured to the aforementioned receptacle or to the above-mentioned medicament administration device by means of external clamping structures such as metal rings, tape bands, etc. In this way, the ends of the puncturable closure are compressed around that portion of the structure to which the closure is attached which is generally a tubular member, the combination of the closure attached to a portion of the structure being referred to as the injection site.
A number of disadvantages are found in the employment of external clamping means. First, if the clamps are not adequately tightened, they are susceptible to disengagement from the structure when the inserted syringe needle is removed from the puncturable closure. In addition, even if the puncturable member remains attached to the structure, leakage of the receptacle contents may occur because of the insufficiently tightened clamping means. Another disadvantge is the somewhat unpleasant appearance of an injection site which includes external clamps.
In U.S. Pat. Nos. 3,900,028 and 4,133,441 (hereinafter `028 and `441, respectively) injection sites that avoid external clamps are described. The disadvantage of the `028 injection site is that it comprises three members interacting to secure the puncturable member in the assemblage, which requires a cumbersome procedure. The latter (`441) site is disadvantageous because it requires an elaborate puncturable membrane.
Injection sites in which a puncturable member is confined in a plastic housing are disclosed in U.S. Pat. Nos. 4,076,023 and 4,000,740. The patented devices require two mated pieces of plastic which are cemented together after a puncturable member is placed inside. In this fashion the member becomes compressibly housed in the mated plastic pieces. The disadvantage of the patented devices is found in their production, since two pieces of plastic are required and the pieces must be cemented together.